Basics: 00 Firehawk 6 spd bolt ons car about 47k miles on it

Problem: around 2500 rpm in first through 4th and when i try to pull out car is bucking and if i push car through it it will back fire and shut the car off

I have replaced the cam and crank sensor a friend of mine locla hooked his hp tuners up and i have about 37 degrees advance at 12% throttle (cruising) goes to 40 at wot like it should so it seems I have too much advance on the timing at lower rpms.

Front cover and crank pulley have never been off the car. Could the chain have come loose and jumped a tooth or should I be looking for something else?

Only other thoughts we had is somehow the reluctor ring came unwelded off the crank or something in the valvetrain being wrong but never had that apart either and car makes no valvetrain noise.

I will be pulling the front cover on friday to check the chain just seeing if anyone had a thought before I took the front of the engine apart.